Python Forum

Hello !

Spyder tells me i've an indentation problem here, line 4, "unexpected indent" :

def A(i, j, Nz, Nr, dr, dz, dt, he, Bir, Biz) :
    if i == 1 :
        if j == 1 :                                                              "partie 1"
            return ((1/(16*dt))+(1/(8*dz**2))+(1/(4*he*he*dr*dr))+(Biz/(8*dz)))
        elif j==Nr :                                                            "partie 3"
            return ((Nr-1)/(2*dt))+(Bir*(Nr-1)/(2*he*he*dr))+(Biz*(Nr-1)/dz)+((Nr-1)/dz**2)+((Nr-1.5)/(2*he*he*dr*dr))
        else :                                                                  "partie 2"
            return (j-1)*((1/(2*dt))+(1/(he*dr)**2)+(1/dz**2)+(Biz/dz))
    elif j==1 :
        if i==Nz :                                                              "partie 7"
            return (1/(16*dt))+(1/(16*dz**2))+(1/(4*dr*dr*he*he))+(Biz/(8*dz))
        else :                                                                  "partie 4"
            return (1/(8*dt))+(2/(8*dz))+(1/(2*he*he*dr*dr))
    elif i==Nz :
        if j==Nr :                                                              "partie 9"
            return ((Nr-1.5)/(he*he*dr*dr))+(Nr-1)*((1/2*dt)+(Bir/(2*he*he*dr))+(Biz/dz)+((1/dz**2)))
        else :                                                                  "partie 8"
            return (j-1)*((1/(2*dt))+(1/(he*he*dr*dr))+(1/(dz**2))+(Biz/dz))
    elif j==Nr :                                                                "partie 6"
        return ((Nr-1.5)/(he*he*dr*dr))+(Nr-1)*((1/(2*dt))+(Bir/(he*he*dr))+(Biz/dz)+(1/dz**2))
    else :                                                                      "partie 5"
        return (j-1)*((1/dt) + (2/(he*dr)**2) + (2/dz**2))

I've tried online website that shows errors in indentation, trying to replace tabs by spaces, avoiding blank lines, etc... Python doesn't want a loop in another loop (i have the same problem with a "while" loop in a "for" loop). It wants me to put the "return" line 4 at the same level as the "if" line 3. If I do it (because I've tried almost everything), the unexpected indentation error goes to the next line, etc. I don't know what to do, I've asked friends and read others forums (and this one too) before but I can't find a solution.

While you're here, it also does me a "syntax error" here, line 5 :

import numpy as np

""" Paramètres : """

tf = 5                                                                         "temps final"
N =  1                                                                         "nombre d'incréments de temps"
t_laser = 1                                                                    "durée de l'émission laser"
dt = tf / N                                                                    "pas de temps"
DT = dt * alpha / H^2                                                          "pas de temps adimensionné"

Thank you for your help !

It's because you put a string on the same line as the if, it sees that as a valid if in one line. Therefore the indentation is not valid. You seem to be using double quotes as comments, you should use an octothorpe (#) instead. That would also fix the other error.

Omg it worked, thank you ! When i learned python, it was ok to put comments with double quotes so I didn't think it could be that :O

Hi,

Quote:When i learned python, it was ok to put comments with double quotes so I didn't think it could be that :O

Never ever, it's alway wrong. Double quotes are a simple strings, nothing else. _ALWAYS_ use the # for comments and nothing else. That's the valid character for marking comments.

Regards, noisefloor

Actually, it works but if they are "alone" on their line and not after something (like my "if" statements), I think I forgot that, my python lessons are a little bit far away in time ahah

The evaluations after return, should shifted in own functions.
Then you can use the functions instead. This will cleanup
the code a little bit. Give them verbs as names.

return ((1/(16*dt))+(1/(8*dz**2))+(1/(4*he*he*dr*dr))+(Biz/(8*dz)))
return ((Nr-1)/(2*dt))+(Bir*(Nr-1)/(2*he*he*dr))+(Biz*(Nr-1)/dz)+((Nr-1)/dz**2)+((Nr-1.5)/(2*he*he*dr*dr))
return (j-1)*((1/(2*dt))+(1/(he*dr)**2)+(1/dz**2)+(Biz/dz))
return (1/(16*dt))+(1/(16*dz**2))+(1/(4*dr*dr*he*he))+(Biz/(8*dz))
return (1/(8*dt))+(2/(8*dz))+(1/(2*he*he*dr*dr))
return ((Nr-1.5)/(he*he*dr*dr))+(Nr-1)*((1/2*dt)+(Bir/(2*he*he*dr))+(Biz/dz)+((1/dz**2)))
return (j-1)*((1/(2*dt))+(1/(he*he*dr*dr))+(1/(dz**2))+(Biz/dz))
return ((Nr-1.5)/(he*he*dr*dr))+(Nr-1)*((1/(2*dt))+(Bir/(he*he*dr))+(Biz/dz)+(1/dz**2))
return (j-1)*((1/dt) + (2/(he*dr)**2) + (2/dz**2))

Instead you'll do this later:

return function_1(dt, dz, he, Biz)

Thank you but actually, I need this to be like I did ! In ordre to correct the expressions, I put comments to show which evaluation corresponds to which "region" of my problem. I've 15 or 20 functions like this, so another function for every evaluation wouldn't be readable, but I appreciate the help !

Hi,

Quote:Actually, it works but if they are "alone" on their line and not after something (like my "if" statements)

Actually it works because technically you define a string without binding it to a name. Whoever told you that this is a comment, it's not. It's super mega ultra wrong. The only way to comment in Python is the #. Nothing else.

Regards, noisefloor

(Jun-21-2019, 11:11 AM)noisefloor Wrote: [ -> ]The only way to comment in Python is the #. Nothing else.

PEP 257 Wrote:String literals occurring elsewhere in Python code may also act as documentation.

I don't think it's quite as clear cut as "nothing else." I think of docstring just as a special kind of comment, and those require triple quotes.

Hi,

Quote: I think of docstring just as a special kind of comment, and those require triple quotes.

I waited for that coming up... Docstrings are for documentation purposes, as the name says. Docstring can be read without looking into the source code, comments not. Comments give _additional_ info when reading through the source code, docstrings give info on how to use a class / function / ... - that's not the same.
And abusing docstrings for comments is still wrong.

Except this, the original post talked about double quotes, not triple quotes.

Regards, noisefloor